9c0cd3f9df
This will make a number of things easier in the future, as well as (finally!) avoiding the Id-smashing problem which has plagued developers for so long. Boy, I'm glad we're not using sup anymore. This update would have been insane otherwise.
791 lines
28 KiB
Groff
791 lines
28 KiB
Groff
.\" manual page [] for pppd 2.0
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.\" $FreeBSD$
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.\" SH section heading
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.\" SS subsection heading
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.\" LP paragraph
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.\" IP indented paragraph
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.\" TP hanging label
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.TH PPPD 8
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.SH NAME
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pppd \- Point to Point Protocol daemon
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.SH SYNOPSIS
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.B pppd
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[
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.I options
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] [
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.I tty_name
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] [
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.I speed
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]
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.SH DESCRIPTION
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.LP
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The Point-to-Point Protocol (PPP) provides a method for transmitting
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datagrams over serial point-to-point links. PPP
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is composed of three parts: a method for encapsulating datagrams over
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serial links, an extensible Link Control Protocol (LCP), and
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a family of Network Control Protocols (NCP) for establishing
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and configuring different network-layer protocols.
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.LP
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The encapsulation scheme is provided by driver code in the kernel.
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.B pppd
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provides the basic LCP, authentication support, and an
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NCP for establishing and configuring the Internet Protocol (IP)
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(called the IP Control Protocol, IPCP).
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.SH FREQUENTLY USED OPTIONS
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.TP
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.I <tty_name>
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Communicate over the named device. The string "/dev/"
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is prepended if necessary. If no device name is given,
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or if the name of the controlling terminal is given,
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.I pppd
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will use the controlling terminal, and will not fork to put itself in
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the background.
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.TP
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.I <speed>
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Set the baud rate to <speed>. On systems such as 4.4BSD and NetBSD,
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any speed can be specified. Other systems (e.g. SunOS) allow only a
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limited set of speeds.
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.TP
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.B asyncmap \fI<map>
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Set the async character map to <map>.
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This map describes which control characters cannot be successfully
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received over the serial line.
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.I pppd
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will ask the peer to send these characters as a 2-byte escape sequence.
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The argument is a 32 bit hex number
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with each bit representing a character to escape.
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Bit 0 (00000001) represents the character 0x00;
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bit 31 (80000000) represents the character 0x1f or ^_.
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If multiple \fBasyncmap\fR options are
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given, the values are ORed together.
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If no \fBasyncmap\fR option is given, no async character map will be
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negotiated for the receive direction; the peer should then escape
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\fIall\fR control characters.
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.TP
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.B auth
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Require the peer to authenticate itself before allowing network
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packets to be sent or received.
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.TP
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.B connect \fI<p>
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Use the executable or shell command specified by \fI<p>\fR to set up the
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serial line. This script would typically use the "chat" program to
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dial the modem and start the remote ppp session.
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.TP
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.B connect-max-attempts \fI<n>
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Attempt dial-out connection to remote system no more than specified number
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of times (default = 1). If the connection is not made, pppd will exit.
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Requires that \fBpersist\fR has been specified.
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.TP
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.B crtscts
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Use hardware flow control (i.e. RTS/CTS) to control the flow of data on
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the serial port.
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.TP
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.B -crtscts
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Disable hardware flow control (i.e. RTS/CTS) on the serial port. If
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neither the \fBcrtscts\fR nor the \fB\-crtscts\fR option is given,
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the hardware flow control setting for the serial port is left
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unchanged.
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.TP
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.B xonxoff
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Use software flow control (i.e. XON/XOFF) to control the flow of data on
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the serial port. This option is only implemented on Linux systems
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at present.
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.TP
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.B defaultroute
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Add a default route to the system routing tables, using the peer as
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the gateway, when IPCP negotiation is successfully completed.
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This entry is removed when the PPP connection is broken.
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.TP
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.B disconnect \fI<p>
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Run the executable or shell command specified by \fI<p>\fR after
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\fIpppd\fR has terminated the link. This script could, for example,
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issue commands to the modem to cause it to hang up if hardware modem
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control signals were not available.
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.TP
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.B escape \fIxx,yy,...
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Specifies that certain characters should be escaped on transmission
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(regardless of whether the peer requests them to be escaped with its
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async control character map). The characters to be escaped are
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specified as a list of hex numbers separated by commas. Note that
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almost any character can be specified for the \fBescape\fR option,
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unlike the \fBasyncmap\fR option which only allows control characters
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to be specified. The characters which may not be escaped are those
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with hex values 0x20 - 0x3f or 0x5e.
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.TP
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.B file \fI<f>
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Read options from file <f> (the format is described below).
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.TP
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.B lock
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Specifies that \fIpppd\fR should use a UUCP-style lock on the serial
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device to ensure exclusive access to the device.
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.TP
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.B mru \fI<n>
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Set the MRU [Maximum Receive Unit] value to <n> for negotiation.
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.I pppd
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will ask the peer to send packets of no more than <n> bytes.
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The minimum MRU value is 128.
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The default MRU value is 1500. A value of 296 is recommended for slow
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links (40 bytes for TCP/IP header + 256 bytes of data).
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.TP
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.B netmask \fI<n>
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Set the interface netmask to <n>, a 32 bit netmask in "decimal dot" notation
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(e.g. 255.255.255.0).
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.TP
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.B dns1 \fI<n>
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If peer asks for primary DNS server, tell them this address,
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a 32 bit ip number in "decimal dot" notation (e.g. 1.2.3.4).
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.TP
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.B dns2 \fI<n>
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If peer asks for secondary DNS server, tell them this address,
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a 32 bit ip number in "decimal dot" notation (e.g. 1.2.3.5).
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.TP
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.B passive
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Enables the "passive" option in the LCP. With this option,
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.I pppd
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will attempt to initiate a connection; if no reply is received from
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the peer,
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.I pppd
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will then just wait passively for a valid LCP packet from the peer
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(instead of exiting, as it does without this option).
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.TP
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.B silent
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With this option,
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.I pppd
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will not transmit LCP packets to initiate a connection until a valid
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LCP packet is received from the peer (as for the `passive' option with
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old versions of \fIpppd\fR).
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.SH OPTIONS
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.TP
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.I <local_IP_address>\fB:\fI<remote_IP_address>
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Set the local and/or remote interface IP addresses. Either one may be
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omitted. The IP addresses can be specified with a host name or in
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decimal dot notation (e.g. 150.234.56.78). The default local
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address is the (first) IP address of the system (unless the
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.B noipdefault
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option is given). The remote address will be obtained from the peer
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if not specified in any option. Thus, in simple cases, this option is
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not required.
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If a local and/or remote IP address is specified with this option,
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.I pppd
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will not accept a different value from the peer in the IPCP
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negotiation, unless the
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.B ipcp-accept-local
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and/or
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.B ipcp-accept-remote
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options are given, respectively.
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.TP
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.B -all
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Don't request or allow negotiation of any options for LCP and IPCP (use
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default values).
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.TP
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.B -ac
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Disable Address/Control compression negotiation (use default, i.e.
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address/control field disabled).
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.TP
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.B -am
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Disable asyncmap negotiation (use the default asyncmap, i.e. escape
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all control characters).
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.TP
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.B -as \fI<n>
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Same as
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.B asyncmap \fI<n>
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.TP
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.B -d
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Increase debugging level (same as the \fBdebug\fR option).
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.TP
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.B -detach
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Don't fork to become a background process (otherwise
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.I pppd
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will do so if a serial device is specified).
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.TP
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.B -ip
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Disable IP address negotiation (with this option, the remote IP
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address must be specified with an option on the command line or in an
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options file).
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.TP
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.B -mn
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Disable magic number negotiation. With this option,
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.I pppd
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cannot detect a looped-back line.
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.TP
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.B -mru
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Disable MRU [Maximum Receive Unit] negotiation (use default, i.e. 1500).
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.TP
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.B -p
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Same as the
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.B passive
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option.
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.TP
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.B -pc
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Disable protocol field compression negotiation (use default, i.e.
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protocol field compression disabled).
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.TP
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.B +ua \fI<p>
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Agree to authenticate using PAP [Password Authentication Protocol] if
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requested by the peer, and
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use the data in file <p> for the user and password to send to the
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peer. The file contains the remote user name, followed by a newline,
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followed by the remote password, followed by a newline. This option
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is obsolescent.
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.TP
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.B +pap
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Require the peer to authenticate itself using PAP.
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.TP
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.B -pap
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Don't agree to authenticate using PAP.
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.TP
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.B +chap
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Require the peer to authenticate itself using CHAP [Challenge
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Handshake Authentication Protocol] authentication.
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.TP
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.B -chap
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Don't agree to authenticate using CHAP.
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.TP
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.B -vj
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Disable negotiation of Van Jacobson style IP header compression (use
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default, i.e. no compression).
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.TP
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.B bsdcomp \fInr,nt
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Request that the peer compress packets that it sends, using the
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BSD-Compress scheme, with a maximum code size of \fInr\fR bits, and
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agree to compress packets sent to the peer with a maximum code size of
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\fInt\fR bits. If \fInt\fR is not specified, it defaults to the value
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given for \fInr\fR. Values in the range 9 to 15 may be used for
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\fInr\fR and \fInt\fR; larger values give better compression but
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consume more kernel memory for compression dictionaries.
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Alternatively, a value of 0 for \fInr\fR or \fInt\fR disables
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compression in the corresponding direction.
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.TP
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.B \-bsdcomp
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Disables compression; \fBpppd\fR will not request or agree to compress
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packets using the BSD-Compress scheme.
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.TP
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.B debug
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Increase debugging level (same as \fB\-d\fR).
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If this
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option is given, \fIpppd\fR will log the contents of all control
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packets sent or received in a readable form. The packets are logged
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through syslog with facility \fIdaemon\fR and level \fIdebug\fR. This
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information can be directed to a file by setting up /etc/syslog.conf
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appropriately (see syslog.conf(5)).
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.TP
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.B \-defaultroute
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Disable the \fBdefaultroute\fR option. The system administrator who
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wishes to prevent users from creating default routes with \fIpppd\fR
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can do so by placing this option in the /etc/ppp/options file.
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.TP
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.B domain \fI<d>
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Append the domain name <d> to the local host name for authentication
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purposes. For example, if gethostname() returns the name porsche, but the
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fully qualified domain name is porsche.Quotron.COM, you would use the
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domain option to set the domain name to Quotron.COM.
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.TP
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.B ipparam \fIstring
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Provides an extra parameter to the ip-up and ip-down scripts. If this
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option is given, the \fIstring\fR supplied is given as the 6th
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parameter to those scripts.
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.TP
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.B modem
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Use the modem control lines. This option is the default. With this
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option,
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.B pppd
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will wait for the CD (Carrier Detect) signal from the modem to be asserted
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when opening the serial device
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(unless a connect script is specified), and it will drop the DTR (Data
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Terminal Ready) signal briefly when the connection is terminated and before
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executing the connect script.
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On Ultrix, this option implies hardware
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flow control, as for the \fBcrtscts\fR option.
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.TP
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.B kdebug \fIn
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Enable debugging code in the kernel-level PPP driver. The argument
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\fIn\fR is a number which is the sum of the following values: 1 to
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enable general debug messages, 2 to request that the contents of
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received packets be printed, and 4 to request that the contents of
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transmitted packets be printed.
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.TP
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.B local
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Don't use the modem control lines. With this option,
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.B pppd
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will ignore the state of the CD (Carrier Detect) signal from the modem and
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will not change the state of the DTR (Data Terminal Ready) signal.
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.TP
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.B mtu \fI<n>
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Set the MTU [Maximum Transmit Unit] value to \fI<n>\fR. Unless the
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peer requests a smaller value via MRU negotiation, \fIpppd\fR will
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request that the kernel networking code send data packets of no more
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than \fIn\fR bytes through the PPP network interface.
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.TP
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.B name \fI<n>
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Set the name of the local system for authentication purposes to <n>.
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.TP
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.B user \fI<u>
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Set the user name to use for authenticating this machine with the peer
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using PAP to <u>.
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.TP
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.B usehostname
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Enforce the use of the hostname as the name of the local system for
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authentication purposes (overrides the
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.B name
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option).
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.TP
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.B remotename \fI<n>
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Set the assumed name of the remote system for authentication purposes
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to <n>.
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.TP
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.B papcrypt
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Indicates that all secrets in the /etc/ppp/pap-secrets file which
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are used for checking the identity of the peer are encrypted, and thus
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pppd should not accept a password which (before encryption) is
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identical to the secret from the /etc/ppp/pap-secrets file.
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.TP
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.B proxyarp
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Add an entry to this system's ARP [Address Resolution Protocol] table
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with the IP address of the peer and the Ethernet address of this
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system.
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.TP
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.B \-proxyarp
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Disable the \fBproxyarp\fR option. The system administrator who
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wishes to prevent users from creating proxy ARP entries with
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\fIpppd\fR can do so by placing this option in the /etc/ppp/options
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file.
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.TP
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.B persist
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Do not exit after a connection is terminated; instead try to reopen
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the connection.
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.TP
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.B login
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Use the system password database for authenticating the peer using
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PAP.
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.TP
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.B noipdefault
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Disables the default behaviour when no local IP address is specified,
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which is to determine (if possible) the local IP address from the
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hostname. With this option, the peer will have to supply the local IP
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address during IPCP negotiation (unless it specified explicitly on the
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command line or in an options file).
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.TP
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.B lcp-echo-interval \fI<n>
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If this option is given, \fIpppd\fR will send an LCP echo-request
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frame to the peer every \fIn\fR seconds. Under Linux, the
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echo-request is sent when no packets have been received from the peer
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for \fIn\fR seconds. Normally the peer should respond to the
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echo-request by sending an echo-reply. This option can be used with
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the \fIlcp-echo-failure\fR option to detect that the peer is no longer
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connected.
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.TP
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.B lcp-echo-failure \fI<n>
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If this option is given, \fIpppd\fR will presume the peer to be dead
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if \fIn\fR LCP echo-requests are sent without receiving a valid LCP
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echo-reply. If this happens, \fIpppd\fR will terminate the
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connection. Use of this option requires a non-zero value for the
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\fIlcp-echo-interval\fR parameter. This option can be used to enable
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\fIpppd\fR to terminate after the physical connection has been broken
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(e.g., the modem has hung up) in situations where no hardware modem
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control lines are available.
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.TP
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.B lcp-restart \fI<n>
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Set the LCP restart interval (retransmission timeout) to <n> seconds
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(default 3).
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.TP
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.B lcp-max-terminate \fI<n>
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Set the maximum number of LCP terminate-request transmissions to <n>
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(default 3).
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.TP
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.B lcp-max-configure \fI<n>
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Set the maximum number of LCP configure-request transmissions to <n>
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(default 10).
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.TP
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.B lcp-max-failure \fI<n>
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Set the maximum number of LCP configure-NAKs returned before starting
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to send configure-Rejects instead to <n> (default 10).
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.TP
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.B ipcp-restart \fI<n>
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Set the IPCP restart interval (retransmission timeout) to <n> seconds
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(default 3).
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.TP
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.B ipcp-max-terminate \fI<n>
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Set the maximum number of IPCP terminate-request transmissions to <n>
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(default 3).
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.TP
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.B ipcp-max-configure \fI<n>
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Set the maximum number of IPCP configure-request transmissions to <n>
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(default 10).
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.TP
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.B ipcp-max-failure \fI<n>
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Set the maximum number of IPCP configure-NAKs returned before starting
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to send configure-Rejects instead to <n> (default 10).
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.TP
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.B pap-restart \fI<n>
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Set the PAP restart interval (retransmission timeout) to <n> seconds
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(default 3).
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.TP
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.B pap-max-authreq \fI<n>
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Set the maximum number of PAP authenticate-request transmissions to
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<n> (default 10).
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.TP
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.B pap-timeout \fI<n>
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Set the maximum time that
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.I pppd
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will wait for the peer to authenticate itself with PAP to
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<n> seconds (0 means no limit).
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.TP
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.B chap-restart \fI<n>
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Set the CHAP restart interval (retransmission timeout for challenges)
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to <n> seconds (default 3).
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.TP
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.B chap-max-challenge \fI<n>
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Set the maximum number of CHAP challenge transmissions to <n> (default
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10).
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.TP
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.B chap-interval \fI<n>
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If this option is given,
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.I pppd
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will rechallenge the peer every <n> seconds.
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.TP
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.B ipcp-accept-local
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With this option,
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.I pppd
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will accept the peer's idea of our local IP address, even if the
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local IP address was specified in an option.
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.TP
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.B ipcp-accept-remote
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With this option,
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.I pppd
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will accept the peer's idea of its (remote) IP address, even if the
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remote IP address was specified in an option.
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.SH OPTIONS FILES
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Options can be taken from files as well as the command line.
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.I pppd
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reads options from the files /etc/ppp/options and ~/.ppprc before
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looking at the command line. An options file is parsed into a series
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of words, delimited by whitespace. Whitespace can be included in a
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word by enclosing the word in quotes ("). A backslash (\\) quotes the
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following character. A hash (#) starts a comment, which continues
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until the end of the line.
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.SH AUTHENTICATION
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.I pppd
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|
provides system administrators with sufficient access control that PPP
|
|
access to a server machine can be provided to legitimate users without
|
|
fear of compromising the security of the server or the network it's
|
|
on. In part this is provided by the /etc/ppp/options file, where the
|
|
administrator can place options to require authentication whenever
|
|
.I pppd
|
|
is run, and in part by the PAP and CHAP secrets files, where the
|
|
administrator can restrict the set of IP addresses which individual
|
|
users may use.
|
|
.LP
|
|
The default behaviour of
|
|
.I pppd
|
|
is to agree to authenticate if requested, and to not
|
|
require authentication from the peer. However,
|
|
.I pppd
|
|
will not agree to
|
|
authenticate itself with a particular protocol if it has no secrets
|
|
which could be used to do so.
|
|
.LP
|
|
Authentication is based on secrets, which are selected from secrets
|
|
files (/etc/ppp/pap-secrets for PAP, /etc/ppp/chap-secrets for CHAP).
|
|
Both secrets files have the same format, and both can store secrets
|
|
for several combinations of server (authenticating peer) and client
|
|
(peer being authenticated). Note that
|
|
.I pppd
|
|
can be both a server
|
|
and client, and that different protocols can be used in the two
|
|
directions if desired.
|
|
.LP
|
|
A secrets file is parsed into words as for a options file. A secret
|
|
is specified by a line containing at least 3 words, in the order
|
|
client name, server name, secret. Any following words on the same line are
|
|
taken to be a list of acceptable IP addresses for that client. If
|
|
there are only 3 words on the line, it is assumed that any IP address
|
|
is OK; to disallow all IP addresses, use "-". If the secret starts
|
|
with an `@', what follows is assumed to be the name of a file from
|
|
which to read the secret. A "*" as the client or server name matches
|
|
any name. When selecting a secret, \fIpppd\fR takes the best match, i.e.
|
|
the match with the fewest wildcards.
|
|
.LP
|
|
Thus a secrets file contains both secrets for use in authenticating
|
|
other hosts, plus secrets which we use for authenticating ourselves to
|
|
others. Which secret to use is chosen based on the names of the host
|
|
(the `local name') and its peer (the `remote name'). The local name
|
|
is set as follows:
|
|
.TP 3
|
|
if the \fBusehostname\fR option is given,
|
|
then the local name is the hostname of this machine
|
|
(with the domain appended, if given)
|
|
.TP 3
|
|
else if the \fBname\fR option is given,
|
|
then use the argument of the first \fBname\fR option seen
|
|
.TP 3
|
|
else if the local IP address is specified with a hostname,
|
|
then use that name
|
|
.TP 3
|
|
else use the hostname of this machine (with the domain appended, if given)
|
|
.LP
|
|
When authenticating ourselves using PAP, there is also a `username'
|
|
which is the local name by default, but can be set with the \fBuser\fR
|
|
option or the \fB+ua\fR option.
|
|
.LP
|
|
The remote name is set as follows:
|
|
.TP 3
|
|
if the \fBremotename\fR option is given,
|
|
then use the argument of the last \fBremotename\fR option seen
|
|
.TP 3
|
|
else if the remote IP address is specified with a hostname,
|
|
then use that host name
|
|
.TP 3
|
|
else the remote name is the null string "".
|
|
.LP
|
|
Secrets are selected from the PAP secrets file as follows:
|
|
.TP 2
|
|
*
|
|
For authenticating the peer, look for a secret with client ==
|
|
username specified in the PAP authenticate-request, and server ==
|
|
local name.
|
|
.TP 2
|
|
*
|
|
For authenticating ourselves to the peer, look for a secret with
|
|
client == our username, server == remote name.
|
|
.LP
|
|
When authenticating the peer with PAP, a secret of "" matches any
|
|
password supplied by the peer. If the password doesn't match the
|
|
secret, the password is encrypted using crypt() and checked against
|
|
the secret again; thus secrets for authenticating the peer can be
|
|
stored in encrypted form. If the \fBpapcrypt\fR option is given, the
|
|
first (unencrypted) comparison is omitted, for better security.
|
|
.LP
|
|
If the \fBlogin\fR option was specified, the
|
|
username and password are also checked against the system password
|
|
database. Thus, the system administrator can set up the pap-secrets
|
|
file to allow PPP access only to certain users, and to restrict the
|
|
set of IP addresses that each user can use. Typically, when using the
|
|
\fBlogin\fR option, the secret in /etc/ppp/pap-secrets would be "", to
|
|
avoid the need to have the same secret in two places.
|
|
.LP
|
|
Secrets are selected from the CHAP secrets file as follows:
|
|
.TP 2
|
|
*
|
|
For authenticating the peer, look for a secret with client == name
|
|
specified in the CHAP-Response message, and server == local name.
|
|
.TP 2
|
|
*
|
|
For authenticating ourselves to the peer, look for a secret with
|
|
client == local name, and server == name specified in the
|
|
CHAP-Challenge message.
|
|
.LP
|
|
Authentication must be satisfactorily completed before IPCP (or any
|
|
other Network Control Protocol) can be started. If authentication
|
|
fails, \fIpppd\fR will terminated the link (by closing LCP). If IPCP
|
|
negotiates an unacceptable IP address for the remote host, IPCP will
|
|
be closed. IP packets can only be sent or received when IPCP is open.
|
|
.LP
|
|
In some cases it is desirable to allow some hosts which can't
|
|
authenticate themselves to connect and use one of a restricted set of
|
|
IP addresses, even when the local host generally requires
|
|
authentication. If the peer refuses to authenticate itself when
|
|
requested, \fIpppd\fR takes that as equivalent to authenticating with
|
|
PAP using the empty string for the username and password. Thus, by
|
|
adding a line to the pap-secrets file which specifies the empty string
|
|
for the client and password, it is possible to allow restricted access
|
|
to hosts which refuse to authenticate themselves.
|
|
.SH ROUTING
|
|
.LP
|
|
When IPCP negotiation is completed successfully,
|
|
.I pppd
|
|
will inform the kernel of the local and remote IP addresses for the
|
|
ppp interface. This is sufficient to create a
|
|
host route to the remote end of the link, which will enable the peers
|
|
to exchange IP packets. Communication with other machines generally
|
|
requires further modification to routing tables and/or ARP (Address
|
|
Resolution Protocol) tables. In some cases this will be done
|
|
automatically through the actions of the \fIrouted\fR or \fIgated\fR
|
|
daemons, but in most cases some further intervention is required.
|
|
.LP
|
|
Sometimes it is desirable
|
|
to add a default route through the remote host, as in the case of a
|
|
machine whose only connection to the Internet is through the ppp
|
|
interface. The \fBdefaultroute\fR option causes \fIpppd\fR to create such a
|
|
default route when IPCP comes up, and delete it when the link is
|
|
terminated.
|
|
.LP
|
|
In some cases it is desirable to use proxy ARP, for example on a
|
|
server machine connected to a LAN, in order to allow other hosts to
|
|
communicate with the remote host. The \fBproxyarp\fR option causes \fIpppd\fR
|
|
to look for a network interface on the same subnet as the remote host
|
|
(an interface supporting broadcast and ARP, which is up and not a
|
|
point-to-point or loopback interface). If found, \fIpppd\fR creates a
|
|
permanent, published ARP entry with the IP address of the remote host
|
|
and the hardware address of the network interface found.
|
|
.SH EXAMPLES
|
|
.LP
|
|
In the simplest case, you can connect the serial ports of two machines
|
|
and issue a command like
|
|
.IP
|
|
pppd /dev/ttya 9600 passive
|
|
.LP
|
|
to each machine, assuming there is no \fIgetty\fR running on the
|
|
serial ports. If one machine has a \fIgetty\fR running, you can use
|
|
\fIkermit\fR or \fItip\fR on the other machine to log in to the first
|
|
machine and issue a command like
|
|
.IP
|
|
pppd passive
|
|
.LP
|
|
Then exit from the communications program (making sure the connection
|
|
isn't dropped), and issue a command like
|
|
.IP
|
|
pppd /dev/ttya 9600
|
|
.LP
|
|
The process of logging in to the other machine and starting \fIpppd\fR
|
|
can be automated by using the \fBconnect\fR option to run \fIchat\fR,
|
|
for example:
|
|
.IP
|
|
pppd /dev/ttya 38400 connect 'chat "" "" "login:" "username"
|
|
"Password:" "password" "% " "exec pppd passive"'
|
|
.LP
|
|
(Note however that running chat like this will leave the password
|
|
visible in the parameter list of pppd and chat.)
|
|
.LP
|
|
If your serial connection is any more complicated than a piece of
|
|
wire, you may need to arrange for some control characters to be
|
|
escaped. In particular, it is often useful to escape XON (^Q) and
|
|
XOFF (^S), using \fBasyncmap a0000\fR. If the path includes a telnet,
|
|
you probably should escape ^] as well (\fBasyncmap 200a0000\fR).
|
|
If the path includes an rlogin, you will need to use the \fBescape
|
|
ff\fR option on the end which is running the rlogin client, since many
|
|
rlogin implementations are not
|
|
transparent; they will remove the sequence [0xff, 0xff, 0x73, 0x73,
|
|
followed by any 8 bytes] from the stream.
|
|
.SH DIAGNOSTICS
|
|
.LP
|
|
Messages are sent to the syslog daemon using facility LOG_DAEMON.
|
|
(This can be overriden by recompiling \fIpppd\fR with the macro
|
|
LOG_PPP defined as the desired facility.) In order to see the error
|
|
and debug messages, you will need to edit your /etc/syslog.conf file
|
|
to direct the messages to the desired output device or file.
|
|
.LP
|
|
The \fBdebug\fR option causes the contents of all control packets sent
|
|
or received to be logged, that is, all LCP, PAP, CHAP or IPCP packets.
|
|
This can be useful if the PPP negotiation does not succeed.
|
|
If debugging is enabled at compile time, the \fBdebug\fR option also
|
|
causes other debugging messages to be logged.
|
|
.LP
|
|
Debugging can also be enabled or disabled by sending a
|
|
SIGUSR1 to the
|
|
.I pppd
|
|
process. This signal acts as a toggle.
|
|
.SH FILES
|
|
.TP
|
|
.B /var/run/ppp\fIn\fB.pid \fR(BSD or Linux), \fB/etc/ppp/ppp\fIn\fB.pid \fR(others)
|
|
Process-ID for \fIpppd\fR process on ppp interface unit \fIn\fR.
|
|
.TP
|
|
.B /etc/ppp/ip-up
|
|
A program or script which is executed when the link is available for
|
|
sending and receiving IP packets (that is, IPCP has come up). It is
|
|
executed with the parameters
|
|
.IP
|
|
\fIinterface-name tty-device speed local-IP-address
|
|
remote-IP-address\fR
|
|
.IP
|
|
and with its standard input,
|
|
output and error streams redirected to \fB/dev/null\fR.
|
|
.IP
|
|
This program or script is executed with the same real and effective
|
|
user-ID as \fIpppd\fR, that is, at least the effective user-ID and
|
|
possibly the real user-ID will be \fBroot\fR. This is so that it can
|
|
be used to manipulate routes, run privileged daemons (e.g.
|
|
\fBsendmail\fR), etc. Be careful that the contents of the
|
|
/etc/ppp/ip-up and /etc/ppp/ip-down scripts do not compromise your
|
|
system's security.
|
|
.TP
|
|
.B /etc/ppp/ip-down
|
|
A program or script which is executed when the link is no longer
|
|
available for sending and receiving IP packets. This script can be
|
|
used for undoing the effects of the /etc/ppp/ip-up script. It is
|
|
invoked with the same parameters as the ip-up script, and the same
|
|
security considerations apply, since it is executed with the same
|
|
effective and real user-IDs as \fIpppd\fR.
|
|
.TP
|
|
.B /etc/ppp/pap-secrets
|
|
Usernames, passwords and IP addresses for PAP authentication.
|
|
.TP
|
|
.B /etc/ppp/chap-secrets
|
|
Names, secrets and IP addresses for CHAP authentication.
|
|
.TP
|
|
.B /etc/ppp/options
|
|
System default options for
|
|
.I pppd,
|
|
read before user default options or command-line options.
|
|
.TP
|
|
.B ~/.ppprc
|
|
User default options, read before command-line options.
|
|
.TP
|
|
.B /etc/ppp/options.\fIttyname
|
|
System default options for the serial port being used, read after
|
|
command-line options.
|
|
.SH SEE ALSO
|
|
.IR chat(8),
|
|
.IR ppp(8)
|
|
.TP
|
|
.B RFC1144
|
|
Jacobson, V.
|
|
.I Compressing TCP/IP headers for low-speed serial links.
|
|
1990 February.
|
|
.TP
|
|
.B RFC1321
|
|
Rivest, R.
|
|
.I The MD5 Message-Digest Algorithm.
|
|
1992 April.
|
|
.TP
|
|
.B RFC1332
|
|
McGregor, G.
|
|
.I PPP Internet Protocol Control Protocol (IPCP).
|
|
1992 May.
|
|
.TP
|
|
.B RFC1334
|
|
Lloyd, B.; Simpson, W.A.
|
|
.I PPP authentication protocols.
|
|
1992 October.
|
|
.TP
|
|
.B RFC1548
|
|
Simpson, W.A.
|
|
.I The Point\-to\-Point Protocol (PPP).
|
|
1993 December.
|
|
.TP
|
|
.B RFC1549
|
|
Simpson, W.A.
|
|
.I PPP in HDLC Framing.
|
|
1993 December
|
|
.SH NOTES
|
|
The following signals have the specified effect when sent to the
|
|
.I pppd
|
|
process.
|
|
.TP
|
|
.B SIGINT, SIGTERM
|
|
These signals cause \fBpppd\fR to terminate the link (by closing LCP),
|
|
restore the serial device settings, and exit.
|
|
.TP
|
|
.B SIGHUP
|
|
This signal causes \fBpppd\fR to terminate the link, restore the
|
|
serial device settings, and close the serial device. If the
|
|
\fBpersist\fR option has been specified, \fBpppd\fR will try to reopen
|
|
the serial device and start another connection. Otherwise \fBpppd\fR
|
|
will exit.
|
|
.TP
|
|
.B SIGUSR2
|
|
This signal causes
|
|
.B pppd
|
|
to renegotiate compression. This can be useful to re-enable
|
|
compression after it has been disabled as a result of a fatal
|
|
decompression error. With the BSD Compress scheme, fatal
|
|
decompression errors generally indicate a bug in one or other
|
|
implementation.
|
|
|
|
.SH AUTHORS
|
|
Drew Perkins,
|
|
Brad Clements,
|
|
Karl Fox,
|
|
Greg Christy,
|
|
Brad Parker,
|
|
Paul Mackerras (paulus@cs.anu.edu.au).
|